This invention relates to a system for identifying the proportional amount of the random noise component and the coherent signal component of an unspecified radio signal at a particular radio frequency. More particularly with the teachings of this invention, one is able to make nearly an instantaneous determination of whether a received unknown signal consists entirely of ramdom noise or a certain amount of coherency. Moreover, the invention provides a method of determining the relative percentage of the noise and coherent components signal.
A variety of instances point to the fact that it is desirable to know whether a received signal, which at first glance appears to be composed of entirely noise, contains a coherent component, however small. For example, when making measurements of cosmic ray showers at any given frequency, it is important, for meterological reasons, to know how much of the signal is atmospheric noise and how much of it is shower ionization. Shower ionization radio emission displays a phase relationship or coherency whereas atmospheric noise has no such established relationship. Another example is that a nuclear detonation from an extremely remote distance produces a weak radio emission hardly discernible from the ambient noise. The emission so produced may be examined at certain frequencies and has an established coherency. It is desirable to detect this detonation and by the use of this invention, the probability of making such a detection is increased because of the increased ability to detect the coherent component of the received signal. These two examples typify the need for a system capable of accurately and quickly determining the noise and coherent components of an unspecified signal.